The cytochrome p450 epoxygenase pathway regulates the hepatic inflammatory response in fatty liver disease

Fatty liver disease is an emerging public health problem without effective therapies, and chronic hepatic inflammation is a key pathologic mediator in its progression. Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid to biologically active epoxyeicosatrienoic acids (EETs), which have potent anti-inflammatory effects. Although promoting the effects of EETs elicits anti-inflammatory and protective effects in the cardiovascular system, the contribution of CYP-derived EETs to the regulation of fatty liver disease-associated inflammation and injury is unknown. Using the atherogenic diet model of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH), our studies demonstrated that induction of fatty liver disease significantly and preferentially suppresses hepatic CYP epoxygenase expression and activity, and both hepatic and circulating levels of EETs in mice. Furthermore, mice with targeted disruption of Ephx2 (the gene encoding soluble epoxide hydrolase) exhibited restored hepatic and circulating EET levels and a significantly attenuated induction of hepatic inflammation and injury. Collectively, these data suggest that suppression of hepatic CYP-mediated EET biosynthesis is an important pathological consequence of fatty liver disease-associated inflammation, and that the CYP epoxygenase pathway is a central regulator of the hepatic inflammatory response in NAFLD/NASH. Future studies investigating the utility of therapeutic strategies that promote the effects of CYP-derived EETs in NAFLD/NASH are warranted

Multi-tissue profiling of oxylipins reveal a conserved up-regulation of epoxide:diol ratio that associates with white adipose tissue inflammation and liver steatosis in obesity

Data sharing statement: The individual-level data used in this study cannot be publicly shared due to ethical approval. Data set will be made available upon request through contact with the corresponding author. For sharing of data within a scientific collaboration any proposal should be directed to the corresponding author. Data will only be shared in accordance with legal frameworks, and when the integrity of the individual study participant can be guaranteed. This will be decided by the corresponding author on a case-by-case basis.Background: Obesity drives maladaptive changes in the white adipose tissue (WAT) which can progressively cause insulin resistance, type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated liver disease (MASLD). Obesity-mediated loss of WAT homeostasis can trigger liver steatosis through dysregulated lipid pathways such as those related to polyunsaturated fatty acid (PUFA)-derived oxylipins. However, the exact relationship between oxylipins and metabolic syndrome remains elusive and cross-tissue dynamics of oxylipins are ill-defined. Methods: We quantified PUFA-related oxylipin species in the omental WAT, liver biopsies and plasma of 88 patients undergoing bariatric surgery (female N = 79) and 9 patients (female N = 4) undergoing upper gastrointestinal surgery, using UPLC-MS/MS. We integrated oxylipin abundance with WAT phenotypes (adipogenesis, adipocyte hypertrophy, macrophage infiltration, type I and VI collagen remodelling) and the severity of MASLD (steatosis, inflammation, fibrosis) quantified in each biopsy. The integrative analysis was subjected to (i) adjustment for known risk factors and, (ii) control for potential drug-effects through UPLC-MS/MS analysis of metformin-treated fat explants ex vivo. Findings: We reveal a generalized down-regulation of cytochrome P450 (CYP)-derived diols during obesity conserved between the WAT and plasma. Notably, epoxide:diol ratio, indicative of soluble epoxide hydrolyse (sEH) activity, increases with WAT inflammation/fibrosis, hepatic steatosis and T2DM. Increased 12,13-EpOME:DiHOME in WAT and liver is a marker of worsening metabolic syndrome in patients with obesity. Interpretation: These findings suggest a dampened sEH activity and a possible role of fatty acid diols during metabolic syndrome in major metabolic organs such as WAT and liver. They also have implications in view of the clinical trials based on sEH inhibition for metabolic syndrome.Wellcome Trust (PS3431_WMIH); Duke-NUS (Intramural Goh Cardiovascular Research Award (Duke-NUS-GCR/2022/0020); National Medical Research Council (OFLCG22may-0011); National Institute of Environmental Health Sciences (Z01 ES025034); NIHR Imperial Biomedical Research Centre

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Postural and cortical responses following visual occlusion in standing and sitting tasks

© 2017 Springer-Verlag Berlin HeidelbergPerturbation-evoked responses (PERs) to a physical perturbation of postural stability have been detected using electroencephalography (EEG). Components of these responses are hypothesized to demonstrate the detection (P1) and evaluation (N1) of postural instability. Despite the important contribution of the visual system to postural control, PERs to a visual perturbation of posture have yet to be reported. Ten healthy young adults were exposed to unpredictable visual occlusion mediated through liquid crystal glasses under two conditions of postural demand: quiet standing and quiet sitting. The participants’ PERs and postural responses were recorded and differences between conditions assessed using Wilcoxon signed-rank tests. In response to unpredictable visual occlusion, both P1 and N1 components of the PER were observed in both postural conditions. The amplitude of the P1 response remained consistent between postural conditions ((Formula presented.), (Formula presented.)), whereas N1 amplitude and postural responses were significantly smaller in the sitting condition ((Formula presented.), (Formula presented.)). This is the first study to demonstrate cortical responses to visual perturbation of posture. The responses to postural perturbation by sudden visual occlusion are similar in nature to that seen in relation to a physical perturbation. In addition, the amplitude of the N1 response is not only consistent with the relative magnitude of the perturbation, but also the underlying postural set, with a larger N1 seen in standing relative to sitting. The study informs the relative importance of vision to postural stability, postural set and provides a protocol to objectively assess sensory-based postural disorders

Effect of Visual Information on Postural Control in Adults with Autism Spectrum Disorder

© 2018 Springer Science+Business Media, LLC, part of Springer Nature Sensory processing difficulties affect the development of sensorimotor skills in individuals with autism spectrum disorder (ASD). However, the effect of sensory information on postural control is unclear in the ASD adult population. The present study examined the effect of visual information on postural control as well as the attentional demands associated with postural control in fourteen adults with ASD and seventeen typically developed adults. The results showed that postural sway and attention demands of postural control were larger in adults with ASD than in typically developed adults. These findings indicate that visual processing used for postural control may be different in adults with ASD. Further research in visual field processing and visual motion processing may elucidate these sensorimotor differences

Use of failure-to-rescue to identify international variation in postoperative care in low-, middle- and high-income countries: a 7-day cohort study of elective surgery

This was an investigator-initiated study funded by Nestle Health Sciences through an unrestricted research grant and by a National Institute for Health Research (UK) Professorship held by R.P. The study was sponsored by Queen Mary University of London